Proton (satellite program)

Proton 1, 2, 3, and 4
A Proton satellite
Mission typeAstronomy
OperatorSoviet Union
COSPAR ID
  • 1965-054A (Proton 1)
  • 1965-087A (Proton 2)
  • 1966-060A (Proton 3)
  • 1968-103A (Proton 4)
Spacecraft properties
ManufacturerOKB-52
Launch mass
  • 12,200 kg (26,900 lb) (Proton 1)
  • 12,200 kg (26,900 lb) (Proton 2)
  • 12,200 kg (26,900 lb) (Proton 3)
  • 17,000 kg (37,000 lb) (Proton 4)
Start of mission
Launch date
  • Proton 1: 16 July 1965 11:16 (1965-07-16UTC11:16Z) UTC
  • Proton 2: 2 November 1965 12:28 (1965-11-02UTC12:28Z) UTC
  • Proton 3: 6 July 1966 12:57 (1966-07-06UTC12:57Z) UTC
  • Proton 4: 16 November 1968 11:40 (1968-11-16UTC11:40Z) UTC
RocketUR-500 (1–3), Proton-K (4)
Launch siteBaikonur Cosmodrome Site 81/23 (1–3), Baikonur Cosmodrome Site 81/24 (4)
End of mission
DisposalDe-orbited
Decay date
  • Proton 1: 11 October 1965 (1965-10-12Z)
  • Proton 2: 6 February 1966 (1966-02-07Z)
  • Proton 3: 6 September 1966 (1966-09-07Z)
  • Proton 4: 24 July 1969 (1969-07-25Z)
Orbital parameters
Reference systemGeocentric
Eccentricity.030 (1–3), .017 (4)
Perigee altitude
  • Proton 1: 183 kilometres (114 mi)
  • Proton 2: 189 kilometres (117 mi)
  • Proton 3: 185 kilometres (115 mi)
  • Proton 4: 248 kilometres (154 mi)
Apogee altitude
  • Proton 1: 589 kilometres (366 mi)[1]
  • Proton 2: 608 kilometres (378 mi)[2]
  • Proton 3: 585 kilometres (364 mi)[3]
  • Proton 4: 477 kilometres (296 mi)
[4]
Inclination63.5° (1–3), 31.5° (4)
Period~92 minutes (1–4)

Proton (‹See Tfd›Russian: протон) ('proton') was a Soviet series of four cosmic ray and elementary particle detecting satellites. Orbited 1965–68, three on test flights of the UR-500 ICBM and one on a Proton-K rocket, all four satellites completed their missions successfully, the last reentering the Earth's atmosphere in 1969.

  1. ^ "Proton 1". NASA Space Science Data Coordinated Archive. Retrieved 23 October 2020.
  2. ^ "Proton 2". NASA Space Science Data Coordinated Archive. Retrieved 23 October 2020.
  3. ^ "Proton 3". NASA Space Science Data Coordinated Archive. Retrieved 23 October 2020.
  4. ^ "Proton 4". NASA Space Science Data Coordinated Archive. Retrieved 23 October 2020.